In addition, the study found that 6 percent of trucks serving the port meet the 2015 standard, 2 percent greater than last year. The 2015 mandate requires trucks to have 2007 model-year engines or newer. The recent truck study was based on 3,100 short-haul trucks that regularly serve terminals on the Tacoma Tideflats.

The Port adopted the clean air goals in early 2008 as part of the Northwest Ports Clean Air Strategy, a partnership among the Port of Tacoma, Port of Seattle and Port Metro Vancouver, B.C. The strategy outlines jointly established short- and long-term clean air goals for ships, cargo-handling equipment, rail, trucks and harbor craft.

In 2009, the Port of Tacoma launched its clean truck program, adopting the regional strategy's goals as standards.